Duma Travel outstanding payment for vouchers

Duma Travel booked accommodation for the Department of water Affairs during the months of September and October 2015 at Gooding's Groves Guesthouse in Franschhoek. The vouchers was for dinner, bed and breakfast and after sending various invoices (they insited on seperate invoices for each voucehr) they still did not pay. The owner spoke to another guesthouse that warned us that Duma Travel do not pay for the vouchers they issue and gave us a contact number of someone at Duma Travel that might help. After contacting this person regarding the oustanding account of R93 700 we received only three payments. Two of the payments was specified via email but the third payment had no specified email to indicate which vouchers was paid. There is still an outstanding amount of R24 000. We have sent various emails that goes unanswered. The agents who issued the vouchers \delete without reading"the emails and the supplier invoice responsible for paying the account"